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Using cURL with Python: A Faster Way to Scrape the Web

Web scraping is more than just a trend—it’s an essential skill for anyone working with data, research, or automation. Whether you're building a research pipeline or extracting data for analysis, understanding how to make effective HTTP requests is crucial. Enter cURL—an often-overlooked tool that packs a punch when it comes to speed and flexibility.
While Python libraries like Requests and HTTPX are popular choices, PycURL can offer performance benefits that are hard to ignore. In this guide, I’ll walk you through using PycURL to make HTTP requests, handling everything from simple GET and POST operations to more advanced use cases like custom headers, XML parsing, and error handling. I’ll also help you compare PycURL’s capabilities against other popular libraries so you can make the right choice for your project.

What is cURL

Before jumping into Python code, let's clear up the basics. cURL is a command-line tool for making network requests. You can use it to interact with APIs, fetch web pages, or send data to a server. For example, these simple commands in your terminal:

# GET request
curl -X GET "https://httpbin.org/get"

# POST request
curl -X POST "https://httpbin.org/post"
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But how does this work in Python? That’s where PycURL comes in. PycURL is a Python wrapper for cURL, giving you the full power of cURL within Python code.

Setting Up: Installing PycURL

First things first: To use cURL with Python, you’ll need the pycurl package. It's simple to install with pip:

pip install pycurl
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Sending HTTP Requests Using PycURL

Let’s dive in. Below, I’ll show you how to make both GET and POST requests using PycURL. We’ll also touch on handling SSL certificates for secure requests.
Sending a GET Request:
Here’s how you can fetch data from a URL with PycURL:

import pycurl
import certifi
from io import BytesIO

# Create a buffer to capture the response
buffer = BytesIO()

# Initialize a cURL object
c = pycurl.Curl()

# Set the URL for the GET request
c.setopt(c.URL, 'https://httpbin.org/get')

# Set the buffer to capture the output
c.setopt(c.WRITEDATA, buffer)

# Use certifi to handle SSL certificates
c.setopt(c.CAINFO, certifi.where())

# Perform the request
c.perform()

# Free up resources
c.close()

# Get the response data
body = buffer.getvalue()

# Decode and print the response
print(body.decode('iso-8859-1'))
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With this code, PycURL sends a GET request to the specified URL, captures the response in a buffer, and prints it once decoded.
Sending a POST Request:
For sending data via POST, PycURL’s POSTFIELDS option comes into play:

import pycurl
import certifi
from io import BytesIO

# Create a buffer for the response
buffer = BytesIO()

# Initialize a cURL object
c = pycurl.Curl()

# Set the URL for the POST request
c.setopt(c.URL, 'https://httpbin.org/post')

# Set the POST data
post_data = 'param1="pycurl"&param2=article'
c.setopt(c.POSTFIELDS, post_data)

# Set the buffer to capture the response
c.setopt(c.WRITEDATA, buffer)

# Handle SSL certificates
c.setopt(c.CAINFO, certifi.where())

# Perform the request
c.perform()

# Free up resources
c.close()

# Get the response and print
body = buffer.getvalue()
print(body.decode('iso-8859-1'))
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This POST request sends a form-like submission to the server and prints the response after decoding.

Custom Headers and Authentication

Many APIs require custom headers or authentication tokens. PycURL makes this easy with the HTTPHEADER option:

import pycurl
import certifi
from io import BytesIO

# Create a buffer for the response
buffer = BytesIO()

# Initialize a cURL object
c = pycurl.Curl()

# Set the URL for the GET request
c.setopt(c.URL, 'https://httpbin.org/get')

# Set custom headers
c.setopt(c.HTTPHEADER, ['User-Agent: MyApp', 'Accept: application/json'])

# Set the buffer to capture the response
c.setopt(c.WRITEDATA, buffer)

# Handle SSL certificates
c.setopt(c.CAINFO, certifi.where())

# Perform the request
c.perform()

# Free up resources
c.close()

# Print the response
body = buffer.getvalue()
print(body.decode('iso-8859-1'))
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This snippet adds custom headers to the request. It's perfect for authenticating API calls or setting content types.

Dealing with XML Responses

When working with APIs that return XML, parsing the response is critical. Here's how you can use PycURL to fetch XML data and parse it:

import pycurl
import certifi
from io import BytesIO
import xml.etree.ElementTree as ET

# Create a buffer for the response
buffer = BytesIO()

# Initialize a cURL object
c = pycurl.Curl()

# Set the URL for the request
c.setopt(c.URL, 'https://www.google.com/sitemap.xml')

# Capture the response in the buffer
c.setopt(c.WRITEDATA, buffer)

# Use certifi for SSL
c.setopt(c.CAINFO, certifi.where())

# Perform the request
c.perform()

# Free up resources
c.close()

# Get the XML response
body = buffer.getvalue()

# Parse XML
root = ET.fromstring(body.decode('utf-8'))

# Print XML tags
print(root.tag, root.attrib)
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Handling Errors Like a Pro

HTTP requests don’t always go smoothly. Robust error handling is critical for production code. Here’s how to catch errors in PycURL:

import pycurl
import certifi
from io import BytesIO

# Initialize a cURL object
c = pycurl.Curl()
buffer = BytesIO()

# Set the URL
c.setopt(c.URL, 'http://example.com')
c.setopt(c.WRITEDATA, buffer)
c.setopt(c.CAINFO, certifi.where())

try:
    c.perform()
except pycurl.error as e:
    errno, errstr = e.args
    print(f'Error: {errstr} (errno {errno})')
finally:
    c.close()
    body = buffer.getvalue()
    print(body.decode('iso-8859-1'))
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This code snippet ensures you handle network errors gracefully and prevents crashes in your application.

Advanced Features: Cookies and Timeouts

cURL has a ton of advanced features. For instance, handling cookies and setting timeouts. Here’s how you can manage cookies and set timeouts with PycURL:

import pycurl
import certifi
from io import BytesIO

buffer = BytesIO()
c = pycurl.Curl()

c.setopt(c.URL, 'http://httpbin.org/cookies')
c.setopt(c.COOKIE, 'cookie_key=cookie_value')  # Handle cookies
c.setopt(c.TIMEOUT, 30)  # Set a timeout

c.setopt(c.WRITEDATA, buffer)
c.setopt(c.CAINFO, certifi.where())

c.perform()
c.close()

body = buffer.getvalue()
print(body.decode('utf-8'))
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Finding the Right Tool for Your HTTP Requests

When comparing PycURL, Requests, HTTPX, and AIOHTTP, each has its strengths. PycURL excels in performance and fine-grained control, with extensive protocol support and the ability to handle streaming. However, it requires a moderate learning curve.
Requests is very easy to use, making it ideal for simpler tasks, though it has limited performance and protocol support. HTTPX offers high performance, supports HTTP/2 and WebSockets, and handles asynchronous requests.
For asynchronous tasks, AIOHTTP and HTTPX are both strong contenders. PycURL is best for heavy lifting and full control, while Requests and HTTPX work well for simplicity, and AIOHTTP is perfect for async work.

Conclusion

Using cURL with Python via PycURL offers powerful performance and control for web scraping and HTTP requests. While it requires a bit of a learning curve, it excels in handling custom headers, cookies, and complex responses like XML. For advanced tasks that demand fine-tuned control, PycURL is a great choice. For simpler needs, libraries like Requests or HTTPX might be more suitable, but PycURL is perfect for heavy lifting and efficiency in web scraping.

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